Frank D. FerrariResearch Zoologist, Emeritus

Research Interests:
Development of Copepods and Related Crustaceans, Patterning of Crustacean Limbs, Taxonomy of Deep-Sea Copepods.

More kinds of arthropods exist today than any other comparable group of animals. An important reason for their success is the marvelous variety of arthropod limbs. Although studies of arthropod development have been carried out for more than 300 years, a basic question about their limbs has gone unasked until recently: how are the limbs patterned during development? Over the last five years, analyses of the comparative morphology of crustacean limb development have begun to reveal information about that question. The protopod of a crustacean limb is patterned distally from the point where the limb joins the body, so that the youngest element of the protopod is always closest to the body. Ramal patterning is more complex; new elements can be added either proximally and distally from a source segment, so that the youngest elements are closest to this patterning center. As a result, determination of homologous segments of a ramus results from a complex analysis and is not a simply a counting exercise; the contemporary application of numerical symbols in a simple, proximodistal progression is a misleading exercise.

Sea water directly above the deep ocean floor is an extremely undersampled habitat. Analyses of this habitat have revealed a wonderful faunal diversity, particularly of calanoid copepods. Almost all of these copepods are new to science. And they are unlike copepods from any other marine habitat. Many of the characters of their morphology have not been observed before, and the states of these characters are evolutionarily derived so that many new genera and families have been established for the new species. The accumulation of myriad kinds of organic matter from primary and secondary production in the water column may account for this faunal diversity, and adaptations to detritivory seems to have played a role in how the fauna of this eternally dark world has been structured.